In the lock industry, the use of dead bolts for security purposes are well known. U.S. Pat. No. 5,257,519 to Miller, discloses a dead bolt lock assembly for use with a combination dial lock assembly. The dead bolt lock assembly includes a housing structure adapted to receive a combination dial lock assembly. The housing structure includes a bolt holdback assembly which prevents extension of a dead bolt into a door strike. The bolt holdback assembly is operable from the inside of the door preventing manipulation of the combination dial on the outside of the door. Arranging the bolt holdback assembly in the housing permits the use of replacement and/or repair of standard or off the shelf type combination locks with the dead bolt assembly.
The Miller dead bolt lock assembly is shown in FIG. 1 and designated by the reference numeral 10. The dead bolt lock assembly includes a base 1 which has as part thereof the dead bolt lock 6. A lock casing 3 of a lock (not shown) is shown supported by the base 1 and positioned between the side walls 5. The dead bolt lock assembly includes a strike 7, a dead bolt operating knob 9 and the bolt holdback knob 11. The lock casing 3 has a lock cover 13 which is removable to gain entry to the lock components of the lock within the lock casing 3.
FIG. 2 shows another prior art dead bolt lock assembly which is manufactured by the Mas-Hamilton group of Lexington, Ky. This dead bolt lock assembly is identical to the lock shown in FIG. 1 in terms of the bolt holdback feature described above. The dead bolt lock assembly of FIG. 2 functions in the same way to obtain the same result as that shown in FIG. 1, i.e., hold the dead bolt back by operation of the knob 11, see FIG. 1 or the dead bolt holdback knob 11' in FIG. 2 (the only difference being the base configuration which does not alter the lock functions). The dead bolt lock assembly 20 of FIG. 2 also includes a base 1' supporting a lock casing 3, the lock casing 3 having the lock cover 13 attached thereto. The dead bolt lock assembly 20 also includes a strike 7 and a dead bolt operating knob 9. The base 1' of the dead bolt lock assembly 20 includes openings 15 which receive fasteners (not shown) to attach the base 1' to a surface. The openings 15 are similar to the FIG. 1 dead bolt lock assembly openings 17 in the sidewalls thereof.
One problem with these types of dead bolt locks is the vulnerability of the access cover 13 to unauthorized removable. Since the access cover 13 is usually secured to the lock casing 3 by screws, the access cover can be removed in a short period of time. The lock within the lock casing can then be altered to permit unauthorized operation of the lock and compromise any secured area that the lock is intended to protect.
Even if other persons may be in the secured area, an individual could quickly remove the lock cover 13 and alter the lock while the other persons are distracted or not paying attention. With an altered lock an unauthorized person could gain access to the secured area at a later time.
In view of the security problem that exposed lock covers present, a need has developed to prevent or protect unauthorized access to the lock components of the lock casing. The present invention solves this need by providing a dead bolt lock access cover which is designed to be removed by an authorized person.